Is solar power a real solution?

In short, yes.

This can be broken down into several questions:

Is solar too expensive?

See this article for analysts who foresee solar becoming as cheap as grid power in 3-5 years.

Also, take a look at First Solar's last quarterly report, which shows PV costs at $1.12 per peak watt (which is very cheap), and that it fell 12% from 1 year ago. I believe their thin-film has efficiency which is a bit below the average for conventional silicon, so Balance of System costs will be a little higher. Their wholesale panels are being sold for about $2.50/Wp, which suggests complete systems, installed, at about $4/Wp. That, in turn, suggests about $.20/kwhr for large, industrial/commercial installations.

Solar costs are now around $.30/kwhr (for retail, rooftop PV) in ideal locations like Southern California, and it looks like large, industrial/commercial installations are indeed achieving about $.20. Given that solar competes with retail electric rates, this is competitive (meaning a total cost that is lower than paying for utility electricity) without subsidies for many customers in S. California. I should think that with continued growth and competition we could expect to see wholesale panels at $1.50/Wp in perhaps the next 3 years, and complete systems, installed, at $3/Wp ( This story suggests costs of less than $2/Wp in several years), which would give us $.15 and grid parity generally in Southern California and many other places. Of course, as long as we have high subsidies we will see very high growth rates, elevated prices and incredible profits - already we're seeing Chinese solar billionaires. It could take a while. OTOH, silicon is also coming down in cost very fast - big producers like Sharp are being very aggressive about this, in order to maintain profits and market share. Ultimately, of course, it depends on the subsidies. As long as Germany is paying around 40 euro cents per KWH, that's how it will be priced in Germany!

At some point, as volumes grow, Germany will have to drop the subsidy levels, and then the rest of the world will begin to reap the benefit of the economies of scale the Germans have paid for.

Solar costs are dropping about 10% or more per year, which puts it at $.12/kwrh in 5 years, and $.06 in 12 (this is a cost-reduction rate which is reasonably well accepted among experts in the area - actually, it may be much faster, with the rate of change in thin-film PV). Solar installation volumes won’t catch up with wind anytime soon. Instead, in around 7-10 years solar is likely to catch up with where wind is now, which is to say that it will be a clearly up and coming large scale power source.

Please note that prices have not fallen quickly, even as costs have fallen. Why? Demand has really gotten ahead of supply. PV supplies are expanding at about 40% per year, but they are only just now beginnging to catch up with demand, especially in Germany. CA has increased subsidies, and France has raised the price they'll pay for PV power, but Germany is gradually reducing theirs. Lately supply seems to be catching up with demand, and prices started to fall in mid 2006.

PV suppliers can still charge a heckuva markup to ration their product, until supplies catch up in the next year or so. For instance, First Solar has a 55% gross profit margin.

Will solar soon be as cheap as coal even when you don't include external costs, like CO2 and mercury?

Yes, when compared to new coal plants - the cost of new coal plants is surprisingly high. Sadly, old, dirty, coal plants are probably unbeatable.

Could solar supply all of our power?

Probably, but it's marginal costs will rise above those of other sources at a much lower % of market penetration, due to intermittency (daily, seasonal and weather-related). The optimal level is around 35% of the overall market as a rough guess.

What solar's advantages?

1st, solar PV is mostly a retail, consumer side technology, and competes with retail pricing. In the US that means that it's competitive at $.10 per KWH, not $.04-.05.

2nd, it provides peak power, which is more expensive for Industrial/Commercial (I/C) consumers, and hopefully will become so for residential consumers.

3rd, most power demand is daytime, especially when you include the I/C demand which DSM has shifted to the night, and which people generally, and erroneously, include as part of "baseload".

4th, PV costs are plummeting - see the last section.

5th, consumers can buy and install PV with very little cooperation from utilities. If they don't care about selling back to the utility then they can cover roughly 75% of their consumption and rarely have unneeded production.

Our energy economy is awfully large, and we currently invest hundreds of billions of dollars in it. That investment just needs to be redirected. Currently PV is labor intensive, and therefore somewhat more expensive than fossil fuels in most places, but that's changing fast - check out Nanosolar.com.

Can solar supply all we need (is it scalable)?

Yes. The earth receives 100,000 terawatts continously from the sun, and humans use the equivalent of 4.5 terawatts on average (15 TW of BTU’s is the standard measurement. That’s equivalent to 1/3x as many electrical BTU's. For instance, in the US 39 quadrillion BTU's are used to produce 13 "quads" of electricity).

Can solar grow fast enough to matter?

Yes, it's doubling more quickly than every 2 years, and manufacturing capital costs are falling, so that growth rate appears sustainable.

Solar PV grew at a 25% annual rate from 1994 to 2000 (doubling twice), and a 40% annual rate from 2000 to 2006 (doubling three times), and the rate of growth is still accelerating (it’s constrained only by the speed manufacturers can ramp up). In 2007 about 3.5 gigawatts worldwide was installed. Solar is definitely here.

Can solar help with Peak Oil?

Yes. First, liquid fuel can be replaced with utility powered plugins and EVs.

It's interesting to note that at current prices PV is cost-effective on any form of transportation that's in use all day - RV's, trucking, bus, rail, water shipping, even aviation. They're all going to hybrid-electric drive trains (or went long ago, in the case of rail), and PV can provide a surprisingly high % of their power (100%, in the case of container boats).

Water shipping is the easiest form of transportation to power renewably. In fact, container vessels could easily run mostly on solar and wind, due to the very low power to surface ratios of these huge boats.

Is it cost effective?

Sure - it's just straightforward calculations: PV can generate power for the equivalent of diesel at $3/gallon (40KWH per gallon @40% efficiency = 16 KWH/gallon; $3/16KWH = bout $.20/KWH.

Could the big container ships that cross the oceans get a substantial fraction of their power this way?

Let's take the Emma Mærsk. With length: 397 metres, and beam: 56 metres, it has a surface area of 22,400 sq m. At 20% efficiency we get about 4.5MW on the ship's deck at peak power. Now, as best I can tell it probably uses about 10MW at 12 knots (very roughly a minimum speed), 20MW at 15 knots, and 65MW (80% of engine rated power) at 25.5 knots (roughly a maximum). So, at minimum speed it could get about 45% of it's power for something close to 20% of the time, for a net of 9%. Now, if we want to increase that we'll need either higher efficiency PV, or more surface area from outriggers or something towed, either of which will increase costs. I suspect that the outriggers would be very cost-effective, but that would involve some design analysis by naval architects.

On using wind propulsion to cut long-distance shipping costs by 10- 50%:
http://www.greencarcongress.com/2006/01/beluga_shipping.htmlhttp://www.skysails.info/index.php?L=1
It's astonishing what can be done with modern materials, computer-aided design, and electronic control systems, to turn the old new again..

Large batteries could be carried for the remainder, to be recharged at frequent port stops, as used to be done with coal. Or, the ships could just slow down - a speed reduction of 25% reduces power consumption by 50%. If this is so easy, why don't we do it already? Because bunker fuel has been so cheap. Now, even at PV's currently relatively high price points it would be cheaper than bunker fuel for propelling ships.

As PV gets cheaper, and oil more expensive, more efficient forms of PV become economic - 10% efficient PV is the cheapest right now, but 40% efficient will get there, and that means a high % of industrial transportation energy from PV. The only exception here is aviation, which is probably limited to getting something around 25% of it's energy consumption from high-efficiency PV.

Is solar being slowed down by the current credit crunch?

Only slightly. One of the largest suppliers has cut it's 2009 forecasted growh from 75% to 58%. One of the largest suppliers has cut it's 2009 forecasted growh from 75% to 58%.